Transcript Functional Anatomy of the Peripheral Nervous System

6
The Nervous
System
Lesson 6.1: Overview of the Nervous System
Lesson 6.2: Transmission of Nerve Impulses
Lesson 6.3: Functional Anatomy of the Central
Nervous System
Lesson 6.4: Functional Anatomy of the Peripheral
Nervous System
Lesson 6.5: Injuries and Disorders of the
Nervous System
Chapter 6: The Nervous System
Lesson 6.1
Overview of the
Nervous System
Organization of the Nervous System
• Two major divisions
– Central Nervous System (CNS)
• Brain
• Spinal Cord
– Peripheral Nervous System (PNS)
• Afferent (sensory) nerves
• Efferent (motor) nerves
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Two Major Divisions
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The Efferent Nerves
• Somatic Nervous System
– Voluntary
• Skeletal muscles
• Autonomic Nervous System
– Involuntary
– Sympathetic
• Fight or Flight
– Parasympathetic
• Rest & Digest
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Nervous Tissues
• Neurons
– Transmit nerve impulses
• Neuroglia
– Support the neurons
– Protect the neurons
– CNS = astrocytes & oligodendrocytes
– PNS = Schwann cells & satellite cells
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Neurons
• Dendrites
– Receive information
• Axons
– Send information
• Cell Body (soma)
– Contain the nucleus
• Myelin Sheath
– Speed up transmission
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Neuron Types by Function
• Sensory Neurons
– “Input” = afferent
– Send impulses toward CNS
• Motor Neurons
– “Output” = efferent
– end impulses away from CNS
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Neuron Structures
• Bipolar
• Unipolar
– One axon
– One dendrite
– Sensory organs
• Multipolar
– One axon
split into two
sections
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– Several dendrites
– Brain & SC
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Chapter 6: The Nervous System
Lesson 6.2
Transmission of
Nerve Impulses
Transmission of Nerve Impulses
• Action Potentials
***Change in cell membrane charge
– Polarized
• Inside of cell membrane is more negative
– Depolarized
• Inside of cell membrane is more positive
– Repolarized
• Reestablishment of polarized state after depolarization
– Refractory period
• Time between completion of action potential & repolarization
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Impulse Transmission
• Transmission at synapses
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Gap junctions
Neurotransmitter
Excitatory effect
Inhibitory effect
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Chapter 6: The Nervous System
Lesson 6.3
Functional Anatomy of the
Central Nervous System
The Brain
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Cerebrum
Cerebellum
Diencephalon
Brain stem
Cerebellum
Meninges
Blood-brain barrier
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Cerebrum
• Cerebral cortex
• Lobes
– Gyrus (raised)
– Sulcus (grooves)
– Fissure (deep)
– Frontal
• Memory, intelligence, behavior,
emotion, motion, smell
– Parietal
• Somatic sensations, speech
– Occipital
• Vision, speech
– Temporal
• Hearing, smell, memory,
speech
• Primary motor cortex
• Primary somatic sensory
cortex
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Cerebrum
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Cerebellum
• Coordinates body movements and balance
– Receives input from eyes, inner ears
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Diencephalon
• Thalamus
– Relay station for sensory and motor information
– Regulates arousal, sleep, consciousness
• Hypothalamus
– Key part of ANS
• Regulates metabolism, R, BP, thirst, hunger, energy, body
temperature, sex drive, pain, pleasure sensation
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Brain Stem
• Midbrain
– Relay of information concerning vision, hearing, alertness
• Pons
– Regulates breathing
• Medulla oblongata
– Regulates HR, BP
– Controls reflexes for coughing,
sneezing, vomiting
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The Brain
• Blood-brain barrier
– Allow water, glucose,
and amino acids
• Meninges
– Dura mater
– Arachnoid mater
– Pia mater
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Spinal Cord
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Chapter 6: The Nervous System
Lesson 6.4
Functional Anatomy
of the Peripheral
Nervous System
Functional Anatomy of the Peripheral
Nervous System
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Nerve structure
Cranial nerves
Spinal nerves and nerve plexuses
Autonomic nervous system
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Nerve Structure
• Endoneurium
– Covers axons
• Perineurium
– Bundles fascicles
• Epineurium
– Wraps nerves
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Spinal Nerves and Nerve Plexuses
• 31 pairs
• Dorsal root
– Sensory input
• Ventral root
– Motor output
• Plexuses
– Branching networks of nerves
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Chapter 6: The Nervous System
Lesson 6.5
Injuries and Disorders of
the Nervous System
Injuries to the Brain and Spinal Cord
• Traumatic brain injury
• Cerebral palsy
• Spinal cord injury
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Traumatic Brain Injury
• Violent impact to head
– Mild
– Moderate
– Severe
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Cerebral Palsy
• Damage to brain
– Before birth
– During birth
– During infancy
• Motor function impairment
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Spinal Cord Injuries
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C1–C3:
C1–C4:
C5–C7:
T1–L5:
Usually fatal
Quadriplegia
Paralysis of lower extremities
Paraplegia
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Common Diseases and Disorders of the
CNS
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Meningitis
Multiple sclerosis
Epilepsy
Parkinson’s disease
Dementia & Alzheimer’s disease
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